Ozone depletion , gradual thinning of Earth ’s ozone layer
in the upper atmosphere caused by the release of
chemical compounds containing gaseous chlorine or
bromine from industry and other human activities. The
thinning is most pronounced in the polar regions,
especially over Antarctica. Ozone depletion is a major
environmental problem because it increases the amount
of ultraviolet (UV) radiation that reaches Earth’s surface,
which increases the rate of skin cancer, eye cataracts ,
and genetic and immune system damage. The Montreal
Protocol , ratified in 1987, was the first of several
comprehensive international agreements enacted to halt
the production and use of ozone-depleting chemicals. As a
result of continued international cooperation on this
issue, the ozone layer is expected to recover over time.